[rocqua]

How expensive, big, and heavy would a hydrogen tank (farm) be if it had to supply a whole winter for, say, 1million people. I ask because one of the bigger transition issues I see in Europe is load shifting from summer surplus to winter deficits, specifically for heating.

[pfdietz]

On such a scale hydrogen would be store underground in solution-mined salt caverns, not above ground in tanks.

Europe has enough salt formations to potentially store millions of GWh of hydrogen, far more than would be needed.

[_ph_]

Why would you want to store enough energy to supply for a whole winter? Wind energy delivers most power during the winter and even solar contributes a bit. The actual amounts to store would be a fraction of that. Of course, that might be the one single good use of hydrogen as a means of storage, but way less storage is needed than most would think.